Three things bug me about Berserk, and has Miura ever made a comment about them?

Firstly, the Black Swordsman arc doesn't quite mesh up with the rest of the storyline, unless my memory is just shit. The relationship between Guts and Puck isn't different from what you see early in the post-eclipse arcs. He also doesn't have the Berserk armor, white hair and I believe Griffith was the king of Midland. Not Falconia. Granted, there's a huge time gap in real life between the prologue and post-eclipse. But has he even tried retconning it? Because there's an inconsistency.

Secondly, Berserk seems to have a lot of different shifts in tone and atmosphere. The black swordsman and post-elcipse arcs aren't that different. But when it's Black Swordsman -> Golden Age -> Golden Age Post-Timeskip/Eclipse -> Post-Eclipse -> what we've had since the new world was created? It's pretty jarring if you read the entire manga in a few sittings.

Lastly, what the hell is with his inability to keep a consistent drawing style for Guts? Guts looks like he's in his 40s now despite being in his early 20s.

Black Swordsman is only vaguely canon. It was published in a different magazine.
Guts changes because Miura got better. Particularly, towards the end of Golden Age, Miura was also working as an assistant drawing Hajime no Ippo, which gave him an excellent grasp on anatomy and muscle. Those changes passed along to Berserk.
The shifts in atmosphere i think are very intentional. the Standalone arcs are all different genres of fantasy. Golden Age was Low Fantasy, Lost Children was Dark Fantasy, and the Fantasia arc is shaping up for some serious Sword and Sorcery. Retribution was its own thing, i see it as a Myth Arc for the series itself.

>>101697266>He also doesn't have the Berserk armor, white hair and I believe Griffith was the king of Midland.
The Black Swordsman is inbetween the golden age and the lost children arc, none of that had happened yet. Also Griffith wasn't King of Midland in the Black Swordsman arc he was still evil batman.